Neutrino Quantum Kinetics in Neutron Star Mergers

Following the collision of two compact objects, an accretion disk forms and from it matter is ejected that sources the universe's heavy elements and that is observable as a kilonova. The amount of ejecta, the types of elements that form, and the appearance of the kilonova depend on the transport of energy in the accretion disk and the relative abundance of neutrons and protons in the ejecta. Both are largely determined by the abundances of electron neutrinos and antineutrinos radiating from the disk. Although an accurate treatment of this transport is a challenging problem in its own right, it is further complicated by the neutrino flavor transformation induced on microscopic scales by neutrino-neutrino interactions. I will describe my work to bring together global general-relativistic neutrino radiation transport and microscopic neutrino mean-field quantum kinetics. I will demonstrate multidimensional simulations of neutrino flavor turbulence, show how to gauge where the neutrinos are unstable to flavor change and how to predict the outcome, and demonstrate that collisions and flavor transformation are inseparable using realistic interactions.